In a case if someone need to enable Quotas for many domain users in many datasets. Because it is working only, with domain users at the moment and not domain groups.
FreeBSD Bash Script to do it:
vim enableuserquotas.sh
Copy past following code:
#!/usr/bin/env bash
# declare an array variables
declare -a Accounts=('DomainUser1' 'DomainUser2' 'DomainUser3')
declare -a shares=('Dataset1' 'Dataset2' 'Dataset3')
Accounts_length=${#Accounts[@]}
shares_length=${#shares[@]}
for((j=0; j<Accounts_length; j++));
do
for((i=0; i<shares_length; i++));
do
zfs set userquota@DOMAIN\\${Accounts[$j]}=250GB DATAPOOL/${shares[$i]}
done
done
chmod +x enableuserquotas.sh